Background: Some non-pathogenic rhizobacteria called Plant Growth Promoting Rhizobacteria (PGPR) possess the capacity to induce in plant defense mechanisms effective against pathogens. Precedent studies showed the ability of Pseudomonas putida BTP1 to induce PGPR-mediated resistance, termed ISR (Induced Systemic Resistance), in different plant species. Despite extensive works, molecular defense mechanisms involved in ISR are less well understood that in the case of pathogen induced systemic acquired resistance. Results: We analyzed the activities of phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX), key enzymes of the phenylpropanoid and oxylipin pathways respectively, in tomato treated or not with P. putida BTP1. The bacterial treatment did not stimulate PAL activity and linoleate-consuming LOX activities. Linolenate-consuming LOX activity, on the contrary, was significantly stimulated in P. putida BTP1-inoculated plants before and two days after infection by B. cinerea. This stimulation is due to the increase of transcription level of two isoforms of LOX: TomLoxD and TomLoxF, a newly identified LOX gene. We showed that recombinant TomLOXF preferentially consumes linolenic acid and produces 13-derivative of fatty acids. After challenging with B. cinerea, the increase of transcription of these two LOX genes and higher linolenic acid-consuming LOX activity were associated with a more rapid accumulation of free 13-hydroperoxy-octadecatrienoic and 13-hydroxy-octadecatrienoic acids, two antifungal oxylipins, in bacterized plants. Conclusion: In addition to the discovery of a new LOX gene in tomato, this work is the first to show differential induction of LOX isozymes and a more rapid accumulation of 13-hydroperoxy-octadecatrienoic and 13-hydroxyoctadecatrienoic acids in rhizobacteria mediated-induced systemic resistance.

The role of bacterial 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity in the interaction between tomato (Lycopersicon esculentum=Solanum lycopersicum) and Pseudomonas brassicacearum was studied in different strains. The phytopathogenic strain 520-1 possesses ACC deaminase activity, an...

Fuzhuan brick tea, a kind of dark tea consumed mainly in the border regions of Southwestern and Northwestern China since the 1860s, is produced from the leaves of Camellia sinensis var. sinensis by microbial fermentation. From this special fermented tea, a new norisoprenoid,...

In our study, we isolated 33 isolates of Actinobacteria which were identified into 16 different genera based on their cultural, morphological and biochemical characteristics. Both soil and rhizosphere soil samples yielded 17 and 16 isolates, which were grouped into nine and seven different...

The article characterizes the biochemical properties of recombinant lipoxygenase-2 in order to obtain reliable information on its mechanism of catalysis. Polyenoic fatty acids were easily utilized by the recombinant lipoxygenase-2. Linoleic acid was the best substrate. Arachidonic and...

Focuses on diagnosis and therapeutic measures of pseudomonal infections. Pathogen responsible for the development of this infection; Discomforts associated with the infection; Antibiotics used in the treatment of this infection; Possibility for pseudomonal pathogen to cause urinary tract infection.

The rhizobacterium Pseudomonas putida BTP1 stimulates induced systemic resistance (ISR) in tomato. A previous work showed that the resistance is associated in leaves with the induction of the first enzyme of the oxylipin pathway, the lipoxygenase (LOX), leading to a faster accumulation of its...

Bacteria need a sufficient supply of iron in ionic form for their metabolism. When living in an environment where this is not possible (as in the soil due to the presence of highly unsoluble ferric oxide hydrates, or in living organisms where iron is bound to peptidic chelators) Fe 3 complexing...

Describes an outbreak in a surgical intensive care unit in France of infection by a single clone of the pathogen Pseudomonas aeruginosa. Overexpression of the clone in an efflux pump system; Stability of the antibiotic resistance pattern in the spread from patient to patient; Control of the...

Pseudomonas avellanae, the causal agent of bacterial canker and decline of hazelnut (Corylus avellana) is currently reported in northern Greece and central Italy. Two lineages of the pathogen can effectively be differentiated by using BOX and ERIC-PCR. Three DNAbased techniques can be used to...